diff --git a/diskimage_builder/elements/gentoo/README.rst b/diskimage_builder/elements/gentoo/README.rst
index 8c7dcdde..89124a65 100644
--- a/diskimage_builder/elements/gentoo/README.rst
+++ b/diskimage_builder/elements/gentoo/README.rst
@@ -30,12 +30,13 @@ Notes:
     default/linux/amd64/17.0/no-multilib
     default/linux/amd64/17.0/hardened
     default/linux/amd64/17.0/no-multilib/hardened
+    default/linux/amd64/17.0/systemd
 
-* You can set the GENTOO_PORTAGE_CLEANUP environment variable to False to
-  prevent cleaning up portage repositories (including overlays).  This makes
-  the image bigger.
+* You can set the `GENTOO_PORTAGE_CLEANUP` environment variable to False to
+  disable the clean up of portage repositories (including overlays).  This
+  will make the image bigger if caching is also disabled.
 
-* Gentoo supports many diferent versions of python, in order to select one
+* Gentoo supports many different versions of python, in order to select one
   you may use the `GENTOO_PYTHON_TARGETS` environment variable to select
   the versions of python you want on your image.  The format of this variable
   is a string as follows `"python2_7 python3_5"`.
@@ -48,3 +49,10 @@ Notes:
 * You can enable overlays using the `GENTOO_OVERLAYS` variable.  In it you
   should put a space separated list of overlays.  The overlays must be in the
   official overlay list and must be git based.
+
+* `GENTOO_EMERGE_ENV` is a bash array containing default environment
+  variables for package install, you can override it with another bash array.
+
+* `GENTOO_EMERGE_DEFAULT_OPTS` can be set to control the default options
+  passed to emerge for all package actions, this includes operations like
+  depclean and preserved-rebuild.
diff --git a/diskimage_builder/elements/gentoo/bin/install-packages b/diskimage_builder/elements/gentoo/bin/install-packages
index b98ec16a..7b25e306 100755
--- a/diskimage_builder/elements/gentoo/bin/install-packages
+++ b/diskimage_builder/elements/gentoo/bin/install-packages
@@ -35,12 +35,12 @@ function show_options {
 function install_gentoo_packages {
     RUN_ONCE_SHM='1'
     if mountpoint -q /dev/shm; then
-        emerge $@
+        emerge ${GENTOO_EMERGE_DEFAULT_OPTS} $@
     elif [[ -k /dev/shm ]]; then
-        emerge $@
+        emerge ${GENTOO_EMERGE_DEFAULT_OPTS} $@
     else
         fix_shm
-        emerge $@
+        emerge ${GENTOO_EMERGE_DEFAULT_OPTS} $@
         unfix_shm
     fi
 }
@@ -58,9 +58,9 @@ while true; do
             if [[ ! -f /usr/portage/profiles ]]; then
                 emerge-webrsync -q
             fi
-            install_gentoo_packages -uDNv --with-bdeps=y --complete-graph=y --jobs=2 @world
+            install_gentoo_packages --update --deep --newuse --complete-graph=y @world
             install_gentoo_packages --verbose=n --depclean
-            install_gentoo_packages -v --usepkg=n @preserved-rebuild
+            install_gentoo_packages --usepkg=n @preserved-rebuild
             etc-update --automode -5
             eselect news read new
             exit 0;
diff --git a/diskimage_builder/elements/gentoo/cleanup.d/05-unmount b/diskimage_builder/elements/gentoo/cleanup.d/05-unmount
new file mode 100755
index 00000000..9b720380
--- /dev/null
+++ b/diskimage_builder/elements/gentoo/cleanup.d/05-unmount
@@ -0,0 +1,35 @@
+#!/bin/bash
+
+if [[ ${DIB_DEBUG_TRACE:-0} -gt 0 ]]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+[[ -n "${TMP_MOUNT_PATH}" ]]
+
+sudo umount -f "${TMP_MOUNT_PATH}"/usr/portage/distfiles
+sudo umount -f "${TMP_MOUNT_PATH}"/usr/portage/packages
+sudo umount -f "${TMP_MOUNT_PATH}"/usr/portage
+
+sudo rm -Rf "${TMP_MOUNT_PATH}"/root/.ccache/* "${TMP_MOUNT_PATH}"/usr/src/* "${TMP_MOUNT_PATH}"/var/cache/edb/dep/* "${TMP_MOUNT_PATH}"/var/cache/genkernel/* "${TMP_MOUNT_PATH}"/var/empty/* "${TMP_MOUNT_PATH}"/var/state/* "${TMP_MOUNT_PATH}"/var/tmp/*
+sudo rm -Rf "${TMP_MOUNT_PATH}"/etc/*- "${TMP_MOUNT_PATH}"/etc/*.old "${TMP_MOUNT_PATH}"/etc/ssh/ssh_host_* "${TMP_MOUNT_PATH}"/root/.*history "${TMP_MOUNT_PATH}"/root/.lesshst "${TMP_MOUNT_PATH}"/root/.ssh/known_hosts "${TMP_MOUNT_PATH}"/root/.viminfo "${TMP_MOUNT_PATH}"/usr/share/genkernel "${TMP_MOUNT_PATH}"/usr/lib64/python*/site-packages/gentoolkit/test/eclean/testdistfiles.tar.gz
+if [[ "${GENTOO_PORTAGE_CLEANUP}" != "False" ]]; then
+    # remove portage files
+    sudo rm -Rf "${TMP_MOUNT_PATH}"/usr/portage/* "${TMP_MOUNT_PATH}"/usr/portage/.git "${TMP_MOUNT_PATH}"/var/cache/portage/distfiles
+fi
+
+# shrink a bit
+for i in $(sudo -- find "${TMP_MOUNT_PATH}"/var/log -type f); do sudo -- sh -c "echo > $i"; done
+sudo find "${TMP_MOUNT_PATH}"/usr/share/man/ -mindepth 1  -maxdepth 1 -path "${TMP_MOUNT_PATH}/usr/share/man/man*" -prune -o -exec rm -rf {} \;
+
+# make it so we don't have to reinstall grub
+if [[ -a ${TMP_MOUNT_PATH}/usr/sbin/grub2-install ]]; then
+    sudo mkdir -p "${TMP_MOUNT_PATH}"/tmp/grub
+    sudo touch "${TMP_MOUNT_PATH}"/tmp/grub/install
+fi
+
+# systemd id
+if [[ "${GENTOO_PROFILE}" == *"systemd"* ]]; then
+    sudo cp /dev/null "${TMP_MOUNT_PATH}"/etc/machine-id
+fi
diff --git a/diskimage_builder/elements/gentoo/environment.d/00-gentoo-envars.bash b/diskimage_builder/elements/gentoo/environment.d/00-gentoo-envars.bash
index 3b55eab5..84350f7f 100644
--- a/diskimage_builder/elements/gentoo/environment.d/00-gentoo-envars.bash
+++ b/diskimage_builder/elements/gentoo/environment.d/00-gentoo-envars.bash
@@ -5,3 +5,13 @@ export GENTOO_PORTAGE_CLEANUP=${GENTOO_PORTAGE_CLEANUP:-'True'}
 export GENTOO_PYTHON_TARGETS=${GENTOO_PYTHON_TARGETS:-'python2_7 python3_5'}
 export GENTOO_PYTHON_ACTIVE_VERSION=${GENTOO_PYTHON_ACTIVE_VERSION:-'python3.5'}
 export GENTOO_OVERLAYS=${GENTOO_OVERLAYS:-''}
+export GENTOO_EMERGE_DEFAULT_OPTS=${GENTOO_EMERGE_DEFAULT_OPTS:-"--binpkg-respect-use --rebuilt-binaries=y --usepkg=y --with-bdeps=y --binpkg-changed-deps=y --quiet --jobs=2"}
+
+# set the default bash array if GENTOO_EMERGE_ENV is not defined as an array
+if ! declare -p GENTOO_EMERGE_ENV  2> /dev/null | grep -q '^declare \-a'; then
+    export GENTOO_EMERGE_ENV=('USE="-build"' 'FEATURES="binpkg-multi-instance buildpkg parallel-fetch parallel-install"')
+fi
+# itterate over the array, exporting each 'line'
+for (( i=0; i<${#GENTOO_EMERGE_ENV[@]}; i++ )); do
+    eval export "${GENTOO_EMERGE_ENV[i]}"
+done
diff --git a/diskimage_builder/elements/gentoo/finalise.d/99-cleanup b/diskimage_builder/elements/gentoo/finalise.d/99-cleanup
index 32a89bf4..1ecf4f06 100755
--- a/diskimage_builder/elements/gentoo/finalise.d/99-cleanup
+++ b/diskimage_builder/elements/gentoo/finalise.d/99-cleanup
@@ -14,14 +14,17 @@ else
     fix_shm
 fi
 
+# sync if needed
+[[ ! -e /usr/portage/profiles ]] && emerge-webrsync
+
 # make world consistant
-USE="-build" emerge -q --complete-graph=y --jobs=2 --update --newuse --deep --with-bdeps=y @world
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --complete-graph=y --update --newuse --deep @world
 # rebuild packages that might need it
-USE="-build" emerge -q --jobs=2 --usepkg=n @preserved-rebuild
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --usepkg=n @preserved-rebuild
 # remove unneeded packages
-USE="-build" emerge --verbose=n --depclean
+emerge --verbose=n --depclean
 # rebuild packages that might have somehow depended on the unneeded packages
-USE="-build" emerge -q --jobs=2 --usepkg=n @preserved-rebuild
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --usepkg=n @preserved-rebuild
 
 # update config files
 etc-update --automode -5
@@ -31,8 +34,6 @@ emerge --verbose=n --depclean
 emaint all -f
 eselect news read all
 
-rm -Rf /root/.ccache/* /usr/src/* /var/cache/edb/dep/* /var/cache/genkernel/* /var/empty/* /var/run/* /var/state/* /var/tmp/*
-rm -Rf /etc/*- /etc/*.old /etc/ssh/ssh_host_* /root/.*history /root/.lesshst /root/.ssh/known_hosts /root/.viminfo /usr/share/genkernel /usr/lib64/python*/site-packages/gentoolkit/test/eclean/testdistfiles.tar.gz
 if [[ "${GENTOO_PORTAGE_CLEANUP}" != "False" ]]; then
     # remove the overlays
     if [[ ${GENTOO_OVERLAYS} != '' ]]; then
@@ -40,23 +41,9 @@ if [[ "${GENTOO_PORTAGE_CLEANUP}" != "False" ]]; then
             layman -d "${OVERLAY}"
         done
     fi
-    # remove portage files
-    rm -Rf /usr/portage/* /usr/portage/.git /var/cache/portage/distfiles
-fi
-
-# shrink a bit
-for i in $(find /var/log -type f); do echo > $i; done
-find /usr/share/man/ -mindepth 1  -maxdepth 1 -path "/usr/share/man/man*" -prune -o -exec rm -rf {} \;
-
-# make it so we don't have to reinstall grub
-if [[ -a /usr/sbin/grub2-install ]]; then
-    mkdir -p /tmp/grub
-    touch /tmp/grub/install
 fi
 
 unfix_shm
 
-# systemd id
-if [[ "${GENTOO_PROFILE}" == *"systemd"* ]]; then
-    cp /dev/null /etc/machine-id
-fi
+# remove within the chroot since /var/run is a symlink
+rm -Rf /var/run/* /run/*
diff --git a/diskimage_builder/elements/gentoo/pre-finalise.d/01-gentoo-cache b/diskimage_builder/elements/gentoo/pre-finalise.d/01-gentoo-cache
new file mode 100755
index 00000000..32887405
--- /dev/null
+++ b/diskimage_builder/elements/gentoo/pre-finalise.d/01-gentoo-cache
@@ -0,0 +1,17 @@
+#!/bin/bash
+
+if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+GENTOO_PORTAGE_DISTFILES_DIR="${DIB_IMAGE_CACHE}/gentoo/distfiles"
+GENTOO_PORTAGE_PACKAGE_DIR="${DIB_IMAGE_CACHE}/gentoo/packages/${GENTOO_PROFILE}"
+GENTOO_PORTAGE_DIR="${DIB_IMAGE_CACHE}/gentoo/portage"
+
+sudo mount --bind "${GENTOO_PORTAGE_DIR}" "${TMP_MOUNT_PATH}"/usr/portage
+mkdir -p "${TMP_MOUNT_PATH}"/usr/portage/distfiles
+sudo mount --bind "${GENTOO_PORTAGE_DISTFILES_DIR}" "${TMP_MOUNT_PATH}"/usr/portage/distfiles
+mkdir -p "${TMP_MOUNT_PATH}"/usr/portage/packages
+sudo mount --bind "${GENTOO_PORTAGE_PACKAGE_DIR}" "${TMP_MOUNT_PATH}"/usr/portage/packages
diff --git a/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-03-enable-overlays b/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-03-enable-overlays
index e2775722..537083eb 100755
--- a/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-03-enable-overlays
+++ b/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-03-enable-overlays
@@ -26,9 +26,9 @@ if [[ ${GENTOO_OVERLAYS} != '' ]]; then
     # depends on that version of openssl.
     echo '=dev-python/cryptography-2.1.4-r2 ~amd64' >> /etc/portage/package.keywords/layman
     echo '=dev-libs/openssl-1.0.2o-r6 ~amd64' >> /etc/portage/package.keywords/layman
-    emerge -q --oneshot --jobs=2 openssl openssh
+    emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot openssl openssh
     # install layman
-    USE="-build" emerge --deep -q --jobs=2 --ignore-built-slot-operator-deps=y layman
+    emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot --deep --ignore-built-slot-operator-deps=y layman
     # sync the initial overlay list
     layman -S
     # enable the various overlays, ignore failures (overlay my already be enabled)
diff --git a/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-04-install-desired-python b/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-04-install-desired-python
index e8b84f03..a689600c 100755
--- a/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-04-install-desired-python
+++ b/diskimage_builder/elements/gentoo/pre-install.d/02-gentoo-04-install-desired-python
@@ -26,11 +26,11 @@ if [[ "${GENTOO_PYTHON_TARGETS}" == *"python3_6"* ]]; then
     echo '~dev-python/setuptools-36.0.1 ~amd64' >> /etc/portage/package.keywords/python
     echo '~dev-python/pyxattr-0.6.0 ~amd64' >> /etc/portage/package.keywords/python
     echo '~sys-apps/kmod-24 ~amd64' >> /etc/portage/package.keywords/python
-    [[ ! -e /usr/lib64/libpython3.6m.so ]] && USE="-build" emerge -1q --jobs=2 dev-lang/python:3.6
+    [[ ! -e /usr/lib64/libpython3.6m.so ]] && emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot dev-lang/python:3.6
 fi
-[[ "${GENTOO_PYTHON_TARGETS}" == *"python3_5"* ]] && [[ ! -e /usr/lib64/libpython3.5m.so ]] && USE="-build" emerge -1q --jobs=2 dev-lang/python:3.5
-[[ "${GENTOO_PYTHON_TARGETS}" == *"python3_4"* ]] && [[ ! -e /usr/lib64/libpython3.4m.so ]] && USE="-build" emerge -1q --jobs=2 dev-lang/python:3.4
-[[ "${GENTOO_PYTHON_TARGETS}" == *"python2_7"* ]] && [[ ! -e /usr/lib64/libpython2.7.so ]] && USE="-build" emerge -1q --jobs=2 dev-lang/python:2.7
+[[ "${GENTOO_PYTHON_TARGETS}" == *"python3_5"* ]] && [[ ! -e /usr/lib64/libpython3.5m.so ]] && emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot dev-lang/python:3.5
+[[ "${GENTOO_PYTHON_TARGETS}" == *"python3_4"* ]] && [[ ! -e /usr/lib64/libpython3.4m.so ]] && emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot dev-lang/python:3.4
+[[ "${GENTOO_PYTHON_TARGETS}" == *"python2_7"* ]] && [[ ! -e /usr/lib64/libpython2.7.so ]] && emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot dev-lang/python:2.7
 # disable python in git if we have to, it only supports python-2.7
 if [[ "${GENTOO_PYTHON_TARGETS}" != *"python2_7"* ]]; then
     echo 'dev-vcs/git -python' >> /etc/portage/package.use/git
@@ -39,9 +39,9 @@ fi
 # this is done one by one with nodeps because it can sometimes have dependency loops
 PYTHON_PACKAGES="dev-python/six dev-python/packaging dev-python/pyparsing dev-python/appdirs dev-python/setuptools dev-python/certifi"
 for PACKAGE in ${PYTHON_PACKAGES}; do
-    USE="-build" emerge -q --oneshot --jobs=2 --with-bdeps=y --update --newuse --deep --nodeps "${PACKAGE}"
+    emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot --update --newuse --deep --nodeps "${PACKAGE}"
 done
-USE="-build" emerge -q --oneshot --jobs=2 --with-bdeps=y --update --newuse --deep --complete-graph=y sys-apps/portage dev-python/pyxattr
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --oneshot --update --newuse --deep --complete-graph=y sys-apps/portage dev-python/pyxattr
 # set the active python version
 eselect python set ${GENTOO_PYTHON_ACTIVE_VERSION}
 # allow these uninstalls to fail as they may not be installed to begin with
@@ -53,12 +53,12 @@ set +e
 set -e
 
 # make world consistant
-USE="-build" emerge -q --complete-graph=y --jobs=2 --update --newuse --deep --with-bdeps=y @world
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --complete-graph=y --update --newuse --deep @world
 # rebuild packages that might need it
-USE="-build" emerge -q --jobs=2 --usepkg=n @preserved-rebuild
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --usepkg=n @preserved-rebuild
 # remove unneeded packages
-USE="-build" emerge --verbose=n --depclean
+emerge --verbose=n --depclean
 # rebuild packages that might have somehow depended on the unneeded packages
-USE="-build" emerge -q --jobs=2 --usepkg=n @preserved-rebuild
+emerge ${GENTOO_EMERGE_DEFAULT_OPTS} --usepkg=n @preserved-rebuild
 
 unfix_shm
diff --git a/diskimage_builder/elements/gentoo/root.d/50-gentoo-cache b/diskimage_builder/elements/gentoo/root.d/50-gentoo-cache
new file mode 100755
index 00000000..84143016
--- /dev/null
+++ b/diskimage_builder/elements/gentoo/root.d/50-gentoo-cache
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
+    set -x
+fi
+set -eu
+set -o pipefail
+
+[ -n "${TARGET_ROOT}" ]
+
+GENTOO_PORTAGE_DISTFILES_DIR="${DIB_IMAGE_CACHE}/gentoo/distfiles"
+GENTOO_PORTAGE_PACKAGE_DIR="${DIB_IMAGE_CACHE}/gentoo/packages/${GENTOO_PROFILE}"
+GENTOO_PORTAGE_DIR="${DIB_IMAGE_CACHE}/gentoo/portage"
+mkdir -p "${GENTOO_PORTAGE_DIR}" "${GENTOO_PORTAGE_PACKAGE_DIR}" "${GENTOO_PORTAGE_DISTFILES_DIR}"
+
+sudo mount --bind "${GENTOO_PORTAGE_DIR}" "${TMP_MOUNT_PATH}"/usr/portage
+mkdir -p "${TMP_MOUNT_PATH}"/usr/portage/distfiles
+sudo mount --bind "${GENTOO_PORTAGE_DISTFILES_DIR}" "${TMP_MOUNT_PATH}"/usr/portage/distfiles
+mkdir -p "${TMP_MOUNT_PATH}"/usr/portage/packages
+sudo mount --bind "${GENTOO_PORTAGE_PACKAGE_DIR}" "${TMP_MOUNT_PATH}"/usr/portage/packages